Amount and Disposition of Striped Bass Discarded in Delaware's Spring Striped Bass Gill-Net Fishery during 2002 and 2003: Effects of Regulations and Fishing Strategies

摘要

The Delaware Division of Fish and Wildlife allocated 95% of the 87,748-kg annual commercial quota for striped bass Morone saxatilis to the spring gill-net fishery. Many striped bass were discarded during the fishery for regulatory and market reasons. The Delaware Division of Fish and Wildlife conducted 45 onboard samples with 10 cooperating netters during the 2002 and 2003 spring gill-net seasons to determine the discard rate and discard mortality rate in this fishery to compare with the 1988 discard and discard mortality rates. Discarded striped bass constituted 29% of the cooperators' total striped bass catch in 2002 and 31% in 2003. Dead discards were 55% of the total discarded striped bass in 2002 and 36% in 2003. Striped bass catch per unit effort, adjusted for the gill-net meters fished, was significantly higher in 2002-2003 than in 1988, but the discard mortality rate was lower than the earlier figure (47% versus 41%). Females comprised almost 60% of dead discards, and many of the discarded females were mature. Eighty-four percent of the discards were above the minimum legal length. The number of sublegal striped bass caught increased as net mesh size decreased. Most discards and all dead discards came from anchor nets. As derived from the discard catch per unit effort of the onboard samples, the estimated number of striped bass discarded dead by Delaware Bay anchor gillnetters was 3,577 during the 2002 season and 4,120 during the 2003 season. The management response by the Delaware Division of Fish and Wildlife to discarding in the spring striped bass gill-net fishery included attempts to curtail anchor netting and encourage drift netting.